First let me say that this site has been an invaluable resource. I spent a great deal of time reading these forums before investing in a whole new medium.

This looks like a friendly community, and I thought I'd share my first egg tempera painting. It's starting to show its final form, but obviously has a long ways to go. It's 18 x 24" (about 46 x 61 cm). This link is to a small gallery on flickr. I'll update it as progress occurs.

Since it's in progress, helpful, constructive criticism is welcome, especially on technical points. Though really, I'm just introducing myself.

Got some work in over the weekend. Hopefully more today.
I've included two details, each revealing two of the three problems I'm struggling with. Any helpful comments are appreciated.

In the detail of the face, you can see some light horizontal cracking. This is a defect in the panel. I didn't notice it until after I'd finished the verdaccio, and there was just a little in the upper left corner. I decided that was acceptable, since this is still a learning experiment. It's worsened, and it makes me grumpy. Certainly worries me about continuing into a second painting using a panel I prepared at the same time. (Cradled maple ply, Gamblin traditional gesso mix.) Guesses as to causes and how to avoid in the future would be great.

In the detail of the hand, you can see that I'm working to control the regularity of brush strokes. I attribute this to practice, and experience with establishing the proper fluidity of paint. In other areas, it may be just that I need a smaller brush.

Overall, the light side of the face has lost some of its color intensity. This is more obvious in certain light. I think today I will try to paint some back in with heavily watered (to become very translucent) hatches. In an oil, I'd put a glaze over the whole face and paint back in the highlights, but I don't see any technique similar to that in egg tempera. A wash would be to uneven. . . .

Matt, I am truly impressed that for your first ET you chose such a complex subject (file drawer, print pattern on blouse, etc.), and are handling it so finely. You mentioned you would do an overall glaze only if it was oil. However you can do it in ET too. To make an egg tempera glaze, just mix the pigment with a much higher ratio of egg medium to the pigment. Transparent pigments work the best, and if you can avoid adding white, even better. Once I was painting a book cover illustration that needed a spooky feeling. It had bright greens in it's rolling hills and a red, pink, orange setting sun, and it was just too cheery looking, so I made a thin transparent orange and after I was sure the painting was dry enough I glazed it with a larger wash brush over the entire piece. The whole painting was transformed by this one glaze. That was my first try at glazing with egg tempera, and it went great! Mostly I glaze over smaller areas, but I just cite this instance to give you courage.

On the crack in your panel, if cross-braces are incorporated into the back of a panel, particularly if it is larger than, say 9" x 12", it is a safer bet to prevent warping. Possibly cradling a 18" x 24" is not adequate bracing to prevent the warp, but to keep it from worsening, consider adding brace support to the back now.

Smaller brushes may help, yes, although it also depends on how much paint is in your brush and how dry your strokes. I hold a Bounty paper towel in my other hand while painting so I can daub the brush tip before applying paint, and this helps me if it's a thinner paint mixture to avoid applying too much paint at once or too unevenly.

Hope this helps, but wow, you are sailing right along! Look forward to seeing further updates on your piece. It's gorgeous!

Its a remarkable first effort - you have such a feeling for the medium. The detail of the hand showing the brushwork is beautiful.

Too bad about the cracking. As you've learned (and I can corroborate from my own experience) the cracks may continue to grow, unpredictably, with changes in moisture and temperature. I have a list of some potential reason for cracking that I'll paste here. One of the most common reasons in a premixed gesso formula is the quality of the rabbit skin glue. So whenever you buy a premixed formula, asked the supplier to send you a sample of the glue used. For example, Fredrix's dry gesso mix is made from a poor quality glue. And Daniel Smith, a perfectly respectable art supplier, sells a poor quality glue. However Gamblin is so focused on using only high quality products that I doubt its the glue. Nonetheless, a good idea to get a sample if you are going to continue to use it, to be sure. Here's the list; I'll throw in the one on pinholes too. Good luck!

Problems with Gesso Panels - Possible Causes (and Possible Solutions)

Cracks that appear within a day or two of gesso application may be caused by one or more of the following:

1. Too high a percentage of glue in your recipe. (Adjust ratio of glue to water. Don’t use less than 11 parts water to one part glue.)

2. Glue is of poor quality or old. (Make sure your glue is 100% pure rabbit skin [collagen] glue; that it is pale in color, and sweet smelling once hydrated. If it is already hydrated, do not use it if it has been kept for too long, smells, or has mold on it.)

3. Gesso is overheated, destroying the glue proteins. (Always use a double boiler. Never heat gesso above 135 degrees, about the temperature of comfortably warm tap water. Use a food thermometer if necessary. Keep gesso just warm enough to stay liquid.)

4. Gesso is dried too quickly using excessive heat, a hair dryer, or a fan. (Let gesso air dry in a warm, but not overly heated room. Be aware of radiators, air conditioning, fans, etc.)

5. The consistency of the gesso is very thick - either because it was initially made so or, over time, water has evaporated and the gesso has thickened. (Aim for gesso with consistency of light cream. Don’t evaporate the water content by overheating. If water does evaporate over the course of the day, re-hydrate gesso to cream-like consistency.)

6. Gesso is applied too thickly. (Gradually build up surface with several thin layers of gesso, versus one or two very thick layers.)

7. A stronger gesso, with a high percentage of glue, is applied over layers of a weaker gesso, with less glue. (Keep the strength of your gesso consistent.)

Cracks that appear at a later date, i.e. weeks or months after your gesso panels have been made, may be caused by the following:

1. A panel is subjected to extremes of heat, cold or humidity. (Store panels in a moderate and stable environment.)

2. A panel is dropped, particularly on its edge. (Store and handle panels with care.)

3. A panel is subjected to too much wet sanding. (Don’t overwork the surface.)

4. The panel itself was defective from the start.
(Make sure solid wood panels are well made and properly cured. If using wood or plywood, cover with linen so surface grain doesn’t telegraph through. Large panels [of any material] may need to be braced to prevent warping, which leads to cracks

3. Gesso is squeezed through cheesecloth.
(Let gesso sit, refrigerated, for a few days. Or, use a mesh strainer instead.)

4. Gesso is applied with sponge brush or air brush. (Try an alternative application method.)

5. Gesso is applied too thickly. (Apply thinly. Several thin coats will dry faster and be smoother than a single thick layer.)

6. There is too great a temperature differential between the surface of the panel and the gesso; i.e. the panel is cool and the gesso is warm, or vice versa. (Don’t work in a cold space. Have panels sit overnight in the room in which you’ll be working, to get them up to room temperature. Don’t overheat gesso. Some commercial gesso makers measure the temperatures of their panels and gesso, to insure they are the same.)

7. Waiting too long between layers, creating surface tension between the layers that encourages air bubbles. (Apply next layer as soon as previous one is dry).

MatG,
If the cracks are running parallel to the wood grain, that's an easy thing to prevent on the next panel. After you size your plywood panel with skin glue, soak some thin cotton or linen in glue, squeeze out some of the excess glue, and spread the cloth across the face of the panel running beyond the edges. Use a card or something similar to squeegee it out from the center to remove bubbles. When dry, trim the excess cloth and begin gessoing.
Dennis

Such wonderful responses from everyone. And I must say that Koo's excellent replies throughout the site are a welcome flurry of activity!

My painting is nearly completed, and I hope to post it soon, but I've taken a full-time teaching job for the next two months which has severely limited my time.

Meanwhile, I'm looking forward to a little more time to read through recent posts more carefully and to respond in the thoughtful manner deserved. Also meanwhile, I plan to use whatever information is here to save the second panel that I prepared at the same time as the one in question, and will soon also proceed with a few beautiful panels that I bought from TrueGesso.